Under gravel Filter Box UGF for Shrimp Tank – Full Set (Small)
The Under Gravel Filter (UGF) is an ideal filtration solution for Caridina shrimp tanks. When used with an active substrate in the UGF, it naturally lowers pH without requiring excessive amounts of soil. The UGF promotes biological filtration by supporting the growth of beneficial bacteria beneath the substrate, helping to maintain clean and healthy water for your shrimp. This filter is perfect for shrimp tanks, offering gentle yet effective filtration while sustaining a balanced ecosystem.

Includes:
Acrylic UGF box
High-quality Ista plate
Uplifting tube & plastic airstone (easy to clean)
Airline tube & valve
Just add soil, place it in the tank, connect a small air pump, and you're good to go.
 
UGF Box Dimensions:
10x10x10 cm (4x4x4 inches)

Suitable for tanks up to 30L
 
Shrimp Mania's comment: This exact box is used by professional breeder Darick from Shrimps Affair in all of his tanks (over 160). 
I've been using under gravel filtration and particularly these UGF boxes in most of my setups for over three years with great success with caridina shrimp. You can find more information about this filter from my videos on my channel.